According to Regulation of Homologation nº 13 of the European Commission for Europe
L:Vehicles with less than 4 wheels:
L1: Displacement less than 50 cc. and whose speed is less than 50 km / h with two wheels
L2: Displacement less than 50 cc. and whose speed is less than 50 km / h with three wheels
L3: Displacement greater than 50 cc. and whose speed is greater than 50 km / h with two wheels
L4: Displacement greater than 50 c. c. and whose speed is higher than 50 km / h with three asymmetric wheels
L5: Maximum authorized mass (M.M.A.) less than 1000 kg and displacement greater than 50 km / h with three asymmetrical wheels
M: Vehicles used to transport people:
M: 4 or 3 wheel vehicles whose M.M.A. is less than 1000 kg
M1: Vehicles with a capacity equal to or less than 9 seats
M2: Vehicles with a capacity greater than 9 seats and one M.M.A. less than 5000 kg
M3: Vehicles with a capacity greater than 9 seats and one M.M.A. greater than 5000 kg
N: Vehicles used for the transport of goods:
N: 4 or 3 wheel vehicles whose M.M.A. is less than 1000 kg
N1: Vehicles whose M.M.A. is less than 3500 kg
N2: Vehicles whose M.M.A. is less than 12000 kg
N3: Vehicles whose M.M.A. is greater than 12000 kg
O: Trailers and semi-trailers:
O1: Trailers and semi-trailers whose M.M.A. is less than 750 kg
O2: Trailers and semi-trailers whose M.M.A. is greater than 750 kg and less than 3500 kg
O3: Trailers and semi-trailers whose M.M.A. exceeds 3500 kg and less than 10000 kg
O4: Trailers and semi-trailers whose M.M.A. exceeds 10000 kg